Enzymes have long been used in the detergent arts to enhance the cleaning of textile substrates. Specific stains on soiled fabrics are particularly responsive to enzymes which cleave specific linkages in the molecules of the stain. For example, enzymes such as proteases and lipases are effective for removing stains such as blood and oils from textile substrates. These stains are protein and lipid fractions from food and fats such as are deposited from body soil. The action of the enzyme on the particular stain assists the surfactant to render overall cleaning improvement.
A particular difficulty associated with working with enzymes is that when they are presented in the form of powders, there have been instances of sensitization to the enzyme in selected individuals. To avoid contact with the enzymes, it has been proposed that the detergent products containing the same be prepared in the form of a liquid, thus minimizing the presence of any dust which may contain the enzyme. However, liquid detergent formulations containing enzymes cause problems relating to the stability of the enzyme. The problem associated with placing enzymes in a liquid environment is that they are subject to decomposition, either by surfactant denaturation or by self-digestion (proteolysis). It is therefore a problem to stabilize enzymes over extended periods of time, particularly when they are exposed to heat which further reduces enzyme stability.
It is therefore desirable to obtain a cleaning composition in a liquid or solid form in which the enzyme contained therein is stabilized such that enhanced synergistic cleaning performance is obtained.